Optical system

An optical system for displaying an object to a viewer is described. The optical system includes an integral first optical assembly, an integral second optical assembly, and an integral third optical assembly disposed between the integral first and second optical assemblies. The integral first optical assembly has a first focal length and includes one or more first optical lenses, and a reflective polarizer. The integral second optical assembly has a second focal length and includes one or more second optical lenses, and a partial reflector having an average optical reflectance of at least 30% for a desired plurality of wavelengths. The integral third optical assembly has a third focal length and includes a curved first phase retarder. The third focal length is greater than a smaller of the first and second focal lengths.